Working Vehicle and Working Machine Having the Working Vehicle

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International Application No. PCT/JP2019/049845, filed on Dec. 19, 2019, which claims the benefit of priority to Japanese Patent Application No. 2018-243531, filed on Dec. 26, 2018. The entire contents of each of these applications are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a working vehicle such as a tractor and to a working machine including the working vehicle, for example.

2. Description of the Related Art

A technique disclosed in Japanese Unexamined Patent Application Publication No. 2018-116608 is known as a technique for creating a traveling route (a scheduled traveling route) on which a working vehicle such as a tractor autonomously travels. In Japanese Unexamined Patent Application Publication No. 2018-116608, a traveling route creating unit generates an inner traveling route constituted of straight traveling routes and a U-turn route connecting the straight traveling routes, and a circuit traveling route for traveling around in an outer circumferential area of an agricultural field.

SUMMARY OF THE INVENTION

A working vehicle includes a traveling vehicle to travel on a scheduled traveling route and including a connector to which a towed vehicle is connected, and an autonomous traveling controller configured or programmed to control autonomous traveling of the traveling vehicle based on the scheduled traveling route and a relative angle between the connector of the traveling vehicle and the towed vehicle connected to the connector.

The autonomous traveling controller is configured or programmed to control steering of the traveling vehicle so that a vehicle position of the traveling vehicle matches the scheduled traveling route.

The autonomous traveling controller is configured or programmed to determine at least one of a steering angle and a steering direction based on the relative angle.

When the scheduled traveling route includes a turn portion to cause the traveling vehicle moving thereon to turn, and the relative angle is less than a turn judgment value, the autonomous traveling controller is configured or programmed to execute a turn control to determine the steering angle and the steering direction so that the vehicle position of the traveling vehicle matches the turn portion. In the turn control, when the relative angle becomes the turn judgment value or more, the autonomous traveling controller is configured or programmed to stop the turn control.

After the stopping of the turn control, when the scheduled traveling route includes a straight-line portion continuously connected to the turn portion, the straight-line portion causing the traveling vehicle moving thereon to travel straight, the autonomous traveling controller is configured or programmed to shift to a multi-point turn control to turn the traveling vehicle in multiple points by changing either the steering angle or the steering direction so that the traveling vehicle enters the straight-line portion.

After the turn control or the multi-point turn control, the autonomous traveling controller is configured or programmed to determine the steering angle and the steering direction so that the towed vehicle is positioned on the straight-line portion.

A working machine includes the working vehicle mentioned above, a towed vehicle connected to the working vehicle, and an angle detector to detect the relative angle.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of preferred embodiments of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings described below.

FIG. 1 is a view showing a block diagram of a working vehicle including a traveling support device.

FIG. 2 is a view showing a connector.

FIG. 3 is a view explaining autonomous traveling.

FIG. 4 is a view showing an example of a map register screen M 1 .

FIG. 5 A is a view of acquiring a contour H 1 of an agricultural field (a field map MP 2 ) based on a traveling locus K 1 .

FIG. 5 B is a view of acquiring the contour H 1 of the agricultural field (the field map MP 2 ) based on an inflection point of the traveling locus K 1 .

FIG. 5 C is a view of acquiring the contour H 1 (the field map MP 2 ) based on switching operations in traveling.

FIG. 6 is a view showing an example of a work setting screen M 2 .

FIG. 7 is a view showing an example of a route setting screen M 3 .

FIG. 8 A is a view showing a unit work section A 3 created in a work area A 2 .

FIG. 8 B is a view showing a unit work section A 3 different from that of FIG. 8 A .

FIG. 9 is an explanation view explaining creation of a scheduled traveling route.

FIG. 10 A is a view that shows traveling in a state where an extension member and a connecting bar are aligned in a straight line in a fore-and-aft direction.

FIG. 10 B is a view that shows traveling in a state where the connecting bar is oblique relative to the extension member.

FIG. 11 A is a view showing states of a working machine turning left and turning in multi-point.

FIG. 11 B is a view showing states of the working machine turning right and turning in multi-point.

FIG. 12 A is a view showing a state where a traveling vehicle and a towed vehicle travel straight with a configuration oblique in one direction.

FIG. 12 B is a view showing a state where the traveling vehicle and the towed vehicle travel straight with a configuration oblique in the other direction.

FIG. 13 is a view showing a flow of the autonomous traveling.

FIG. 14 is a side overall view of a tractor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings. The drawings are to be viewed in an orientation in which the reference numerals are viewed correctly.

With reference to the drawings, preferred embodiments of the present invention will be described below.

FIG. 1 shows a block diagram of a working machine. In the present preferred embodiment, the working machine includes a working vehicle 1 and a towed vehicle 2 . The working vehicle 1 is a tractor configured to tow the towed vehicle 2 , for example.

The tractor, one of the working vehicles, will be described.

As shown in FIG. 14 , the tractor 1 includes a traveling vehicle 3 including a traveling device 7 , a prime mover 4 , and a transmission device 5 . The traveling device 7 includes front wheels 7 F and rear wheels 7 R. Each of the front wheels 7 F may be of a tire type or crawler type. Each of the rear wheels 7 R may also be of the tire type or crawler type. The prime mover 4 is a diesel engine, an electric motor, or the like. The transmission device 5 is configured to switch a propulsion force of the traveling device 7 by shifting gears, and also to switch a traveling direction of the traveling device 7 between forward and backward. A cabin 9 is mounted on the traveling vehicle 3 , and a driver seat 10 is provided in the cabin 9 .

A connector 8 to be connected to the towed vehicle 2 is provided in a rear portion of the traveling vehicle 3 . By connecting the towed vehicle 2 to the connector 8 , the traveling vehicle 3 can tow the towed vehicle 2 . The towed vehicle 2 is a trailer or the like. The towed vehicle 2 includes a connecting bar 2 a fixed to a frame of the towed vehicle 2 with fasteners such as bolts, and is not able to swing in a width direction. The connecting bar 2 a may be fixed to the frame of the towed vehicle 2 by welding, for example. An insertion hole 2 c is located in a front end of the connecting bar 2 a.

As shown in FIG. 2 , the connector 8 is, for example, a towing hitch, and includes an extension member 8 a extending rearwardly from the traveling vehicle 3 , and a pivot pin 8 b located at a rear end of the extension member 8 a . A front portion of the extension member 8 a is fixed to a transmission case, a differential case, or the like of the transmission device 5 with fasteners such as bolts, and is not able to swing in a width direction. A rear portion of the extension member 8 a includes an upper wall 8 a 1 and a lower wall 8 a 2 separated from the upper wall 8 a 1 , and the pivot pin 8 b penetrates through the upper wall 8 a 1 and the lower wall 8 a 2 . By positioning the connecting bar 2 a of the towed vehicle 2 between the upper wall 8 a 1 and the lower wall 8 a 2 and inserting the pivot pin 8 b into an insertion hole of the connecting bar 2 a , the towed vehicle 2 can be connected to the connector 8 .

As shown in FIG. 1 , the tractor 1 includes a steering device 11 . The steering device 11 includes a handling wheel (that is, a steering wheel) 11 a , a rotation shaft (that is, a steering shaft) 11 b that rotates with the rotating of the steering wheel 11 a , and an assist mechanism (that is, a power steering mechanism) 11 c that assists the steering of the steering wheel 11 a . The auxiliary mechanism 11 c includes a hydraulic pump 21 , a control valve 22 to which hydraulic fluid output from the hydraulic pump 21 is supplied, and a steering cylinder 23 to be operated by the control valve 22 . The control valve 22 is a solenoid valve configured to be operated according to a control signal. For example, the control valve 22 is a three-position switching valve configured to be switched through movement of a spool or the like. The control valve 22 can also be switched through the steering of the steering shaft 11 b . The steering cylinder 23 is connected to an arm (that is, a knuckle arm) 24 that changes orientations of the front wheels 7 F.

Thus, when the steering wheel 11 a is operated, a switching position and an opening aperture of the control valve 22 are switched according to the operation of the steering wheel 11 a , and the steering cylinder 23 is extended and contracted rightward or leftward according to the switching position and the opening aperture of the control valve 22 , thus changing the steering directions of the front wheels 7 F. The above-mentioned configuration of the steering device 11 is just an example, and a configuration of the steering device 11 is not limited to the above-mentioned configuration.

The tractor 1 includes a positioning device 40 . The positioning device 40 is configured to detect its own position (that is, positioning information including latitude and longitude) with satellite positioning systems (that is, positioning satellites) such as D-GPS, GPS, GLONASS, HOKUTO, GALILEO, and MICHIBIKI. That is, the positioning device 40 receives satellite signals (that is, positions of the positioning satellites, transmission times, correction information, and the like) transmitted from the positioning satellites, and detects a position of the tractor 1 (for example, latitude, longitude), that is, detects a vehicle position, based on the satellite signals. The positioning device 40 includes a receiver 41 and an inertial measurement unit (IMU) 42 . The receiver 41 includes an antenna and the like to receive satellite signals transmitted from the positioning satellites, and is attached to the traveling vehicle 3 separately from the inertial measurement unit 42 . In the present preferred embodiment, the receiver 41 is attached to the traveling vehicle 3 , that is, the cabin 9 . The attachment location of the receiver 41 is not limited to that of the present preferred embodiment.

The inertial measurement unit 42 includes an acceleration sensor to detect acceleration, a gyro sensor to detect angular velocity, and the like. The inertial measurement unit 42 is located below the traveling vehicle 3 , for example, below the driver seat 10 , and can detect a roll angle, a pitch angle, a yaw angle, and the like of the traveling vehicle 3 .

As shown in FIG. 1 , the tractor 1 includes a controller 60 . The controller 60 is configured or programmed to control a traveling system and a work system of the tractor 1 .

The controller 60 is configured or programmed to include an autonomous traveling controller 61 to control autonomous traveling of the tractor 1 . The autonomous traveling controller 61 includes electrical and electronic circuits provided in the controller 60 , computer programs stored in a CPU, or the like. When autonomous traveling starts, the autonomous traveling controller 61 controls the control valve 22 of the steering device 11 so that the traveling vehicle 3 travels on the scheduled traveling route L 1 . In addition, when autonomous traveling starts, the autonomous traveling controller 61 controls a vehicle speed (that is, a velocity) of the tractor 1 by automatically gear-shifting the transmission device, changing a revolving speed of the prime mover, and the like.

As shown in FIG. 3 , when a deviation between a vehicle position and the scheduled traveling route L 1 is less than a threshold value in autonomous traveling by the tractor 1 , the autonomous traveling controller 61 maintains a rotation angle of the steering shaft (that is, a rotation shaft) 11 b . When the deviation between the vehicle position and the scheduled travel route L 1 is the threshold value or more and the tractor 1 is located leftward from the scheduled travel route L 1 , the autonomous traveling controller 61 rotates the steering shaft 11 b so that a steering direction of the tractor 1 is orientated to the right. When the deviation between the vehicle position and the scheduled travel route L 1 is the threshold value or more and the tractor 1 is located rightward from the scheduled travel route L 1 , the autonomous traveling controller 61 rotates the steering shaft 11 b so that a steering direction of the tractor 1 is orientated to the left. In the above-mentioned preferred embodiment, a steering angle of the steering device 11 is changed based on the deviation between the vehicle position and the scheduled traveling route L 1 . However, when the direction of the scheduled traveling route L 1 differs from a direction (referred to as a vehicle direction) F 1 of a movement direction (referred to as a traveling direction) of the tractor 1 (that is, the traveling vehicle 3 ), that is, when an angle θg of the vehicle direction F 1 relative to the scheduled traveling route L 1 is a threshold value or more, the autonomous traveling controller 61 may set a steering angle so that the angle θg is zero (that is, the vehicle direction F 1 matches a direction of the scheduled traveling route L 1 ). The autonomous traveling controller 61 may also determine a final steering angle in autonomous steering according to a steering angle obtained based on the deviation (that is, a positional deviation) and a steering angle obtained based on the direction (that is, a directional deviation). The setting of the steering angle in autonomous steering in the above-mentioned preferred embodiment is just an example and is not limited thereto.

As described above, the controller 60 is capable of controlling the tractor 1 (that is, the traveling vehicle 3 ) to autonomously travel.

The tractor 1 includes a traveling support device 100 . The traveling support device 100 is a display device installed near the driver seat 10 . The following description assumes that the traveling support device 100 is a display device.

The display device includes a display 50 that may be any of a liquid crystal panel, a touch panel, or other panels, and is capable of displaying various information relating to the tractor 1 , in addition to information for supporting the traveling of the tractor 1 .

The display device includes a map register 101 and a map storage 102 . The map register 101 includes electrical and electronic components mounted in the display device, a computer program installed in the display device, and other components. The map storage 102 may be non-volatile memory, or the like. The map register 101 registers a contour of a predetermined agricultural field, for example, a position corresponding to a contour of a predetermined agricultural field.

As shown in FIG. 4 , when an operator (that is, a driver) performs a predetermined operation on the display device, the map register 101 displays a map register screen M 1 on the display 50 of the display device. In the map register screen M 1 , a map MP 1 including a map of a field, a vehicle position VP 1 of the tractor 1 , and field identification information such as a field name and a field management number are displayed. In addition to the image data showing the field, position information such as latitude and longitude is associated with the map MP 1 . When the tractor 1 enters the field and travels around in the field, the map register screen M 1 displays the current vehicle position VP 1 that is detected by the positioning device 40 during the traveling of the tractor 1 in the field. When the tractor 1 stops traveling around in the field and a registration button 51 displayed on the map register screen M 1 is selected, the map register 101 uses, as a contour (that is, an outline) H 1 of field, a traveling locus K 1 obtained based on a plurality of vehicle positions obtained during the traveling of the tractor 1 as shown in FIG. 5 A , and registers the field map MP 2 represented by the contour H 1 together with the field identification information.

As shown in FIG. 5 B , the map register 101 may calculate inflection points based on the traveling locus represented by the vehicle position VP 1 and register a contour K 2 connecting the inflection points to one another as the contour H 1 of field (that is, the field map MP 2 ). As shown in FIG. 5 C , a driver or another person may select edge portions of the field with use of a switch or the like provided on the tractor 1 traveling around, and the contour K 3 connecting the selected edge portions to one another may be registered as the contour H 1 (that is, the field map MP 2 ). The above-mentioned method of registering a field is just an example and is not limited thereto. The contour of field, that is, the field map MP 2 , may be data indicated in positions (that is, latitude and longitude), data indicated in a coordinate system (that is, X-axis and Y-axis), or data in other expressions.

The map storage 102 stores the field map MP 2 showing a contour (that is, an outline) registered by the map register 101 . That is, the map storage 102 stores the field map MP 2 , i.e., data indicating the contour of field (that is, data for representing a predetermined field).

The display device (that is, the traveling support device 100 ) is configured to create, for a predetermined field, the scheduled traveling route L 1 to be used in autonomously traveling the tractor 1 . The traveling support device 100 includes a route creating unit 105 to create the scheduled traveling route L 1 and a width acquisition unit 107 . The route creating unit 105 and the width acquisition unit 107 include electrical and electronic circuits provided in the display device, computer programs stored in the display device, or the like.

As shown in FIG. 6 , when an operator (that is, a driver) performs a predetermined operation on the display device, the route creating unit 105 displays the work setting screen M 2 . The work setting screen M 2 includes a field input portion 80 and a field display portion 81 . The field input portion 80 allows input of field identification information such as a field name, a management number of field, and the like. The field display portion 81 displays the field map MP 2 showing a predetermined field corresponding to the field identification information input in the field input portion 80 . That is, the route creating unit 105 requests, from the map storage 102 , the field map MP 2 corresponding to the field identification information input to the field input portion 80 , and displays, on the field display portion 81 , the field map MP 2 transmitted from the map storage 102 .

In the work setting screen M 2 , when a headland width W 1 is input in the headland width input portion 82 and the headland setting button 83 is selected, the route creating unit 105 displays a work area A 2 , excluding a headland area A 1 , in the field map MP 2 displayed in the field display portion 81 . For example, the route creating unit 105 sets an area surrounded by a contour H 2 , which is formed by offsetting the contour H 1 of the field map MP 2 inward by the headland width W 1 , as the work area A 2 . In the work setting screen M 2 , the work area A 2 may be set in the field map MP 2 by designating, with a pointer or the like, a position of an outline of the work area A 2 on the field map MP 2 displayed in the field display portion 81 .

As shown in FIG. 7 , when the setting of the work area A 2 is completed, the route creating unit 105 switches display of the display device (that is, the traveling support device 100 ) from the work setting screen M 2 to a route setting screen M 3 . In the route setting screen M 3 , it is possible to set the scheduled traveling route L 1 in an area including the work area A 2 in a field. The route setting screen M 3 includes a route display portion 85 that displays the scheduled travel route L 1 and a width input portion 88 . The width acquisition unit 107 acquires a towing width W 2 input to the width input portion 88 . The towing width W 2 of the towed vehicle 2 is a width of the towed vehicle 2 .

When the width acquisition unit 107 acquires the towing width W 2 , the route creating unit 105 creates, in the work area A 2 , a plurality of unit work sections A 3 in which the towed vehicle 2 works by dividing the work area A 2 vertically or horizontally by the towing width W 2 , as shown in FIG. 8 A . That is, the route creating unit 105 creates a plurality of unit work sections A 3 of the same width as the towing width W 2 in the work area A 2 . As shown in FIG. 8 B , the route creating unit 105 may create a plurality of unit work sections A 3 each having a width W 4 , which is a width obtained by eliminating an overlap width W 3 from the towing width W 2 , in the work area A 2 . The overlap width W 3 can be input in the route setting screen M 3 . That is, the route creating unit 105 sets, as the unit work area A 3 , the minimum unit area in which a work is performed on the field by the towed vehicle 2 when the traveling vehicle 3 connected to the towed vehicle 2 travels.

The route creating unit 105 includes a straight-line creating part 105 A and a turn creating part 105 B. As shown in FIG. 9 , the straight-line creating part 105 A creates, for each unit work section A 3 in the work area A 2 , a straight-line portion (that is, a straight-line route) L 1 a configured to make the traveling vehicle 3 moving thereon travel straight. That is, the straight-line creating part 105 A creates, for example, a straight-line portion L 1 a at a width directional center of the unit work section A 3 , the straight-line portion L 1 a connecting both longitudinal directional ends of the unit work section A 3 to each other. In addition, the turn creating part 105 B creates a turn portion (that is, a turn route) L 1 b by connecting adjoining straight-line portions L 1 a to each other, the turn portion L 1 b being configured to make the traveling vehicle 3 moving thereon turn.

The autonomous traveling controller 61 controls autonomous traveling based on a relative angle θA between the connector 8 of the traveling vehicle 3 and the towed vehicle 2 connected to the connector 8 . The working machine includes an angle detector 90 configured to detect the relative angle θA with light, magnetism, or the like. The angle detector 90 includes a magnet (or magnets) attached to a swingable portion (that is, a front end of the connecting bar 2 a of the towed vehicle 2 ) and a magnetic sensor attached to a stationary portion (that is, the upper wall 8 a 1 or lower wall 8 a 2 of the extension 8 a ). In the angle detector 90 , the relative angle θA is detected by sensing a change in magnetic field of the magnet with the magnetic sensor. As shown in FIG. 10 A , when the connecting bar 2 a and the extension member 8 a are aligned in a straight line in a fore-and-aft direction, the angle detector 90 detects that the relative angle θA is zero. As shown in FIG. 10 B , when the extension member 8 a crosses (bends) with respect to the connecting bar 2 a , the angle detector 90 detects the relative angle θA according to a crossing degree. The above-mentioned angle detector 90 is just an example and is not limited thereto, and may include an infrared sensor, a rotary encoder, a device to capture an image and detects an angle from the captured image, a device to detect an angle based on extending and contracting of a cylinder or the like, or any other configuration.

The automatic traveling controller 61 determines at least one of the steering angle and the steering direction based on the relative angle θA. For example, in a state where autonomous traveling is being performed on the straight-line portion L 1 a and the turn portion L 1 b , when the relative angle θA is larger than a predetermined judgment value and a distance between the traveling vehicle 3 and the towed vehicle 2 defined by the connector 8 is short, the autonomous traveling controller 61 reduces the relative angle θA by setting a steering angle of the steering device 11 to be smaller than the current steering angle, and reduces the relative angle θA by changing a steering direction to a direction in which the traveling vehicle 3 and the towed vehicle 2 are separated further away from each other.

FIGS. 11 A and 11 B show a state where the traveling vehicle 3 and the towed vehicle 2 are turning in the headland area A 1 .

As shown in FIGS. 11 A and 11 B , the autonomous traveling controller 61 monitors the relative angle θA when the traveling vehicle 3 turns while traveling forward on the turn area L 1 b . When the relative angle θA detected by the angle detector 90 is less than a turn judgment value OT, the autonomous traveling controller 61 determines steering angles θL 1 and θR 1 based on the turn portion L 1 b and the vehicle position to execute a turn control so that the vehicle position of the traveling vehicle 3 matches the turn portion L 1 b . That is, when the relative angle θA is less than the turn judgment value OT, the autonomous traveling controller 61 continues the turn control in which the turning is performed according to the steering angles θL 1 and θR 1 determined based on the turn portion L 1 b and the vehicle position.

On the other hand, in a state when the traveling vehicle 3 turns while traveling forward on the turn portion L 1 b , the autonomous traveling controller 61 stops the turn control when the relative angle θA is the turn judgment value θT or more. In a state where the steering device 11 turns the traveling vehicle 3 to the right, the autonomous traveling controller 61 also stops the turn control when the relative angle θA is the turn judgment value θT or more.

When the autonomous traveling controller 61 stops the turn control, the control shifts to a multi-point turn control. In the multi-point turn control, the traveling vehicle 3 switchbacks the steering in multi-point by changing the steering angles θL 1 and θR 1 so that the traveling vehicle 3 can enter on the straight-line portion L 1 a continuously connecting to the turn portion L 1 b.

As shown in FIG. 11 A , in a state where the steering device 11 turns the traveling vehicle 3 to the left, the autonomous traveling controller 61 shifts from the turn control to the multi-point turn control when the relative angle θA is the turn judgment value θT or more at a point P 60 . In the multi-point turn control, the steering direction is changed from the left to the right by the steering device 11 as shown by a switchback FG 1 , and the traveling vehicle 3 travels forward. In the switchback FG 1 , the forward-traveling is performed with the steering direction changed from the left to the right, and thus the relative angle θA gradually decreases. When the traveling vehicle 3 and the towed vehicle 2 are in a straight line, that is, when the relative angle θA becomes zero, the steering angle θL 1 of the steering device 11 is set to be substantially zero, and the traveling vehicle 3 travels backward, as shown in a switchback FG 2 . In the switchback FG 2 , the traveling vehicle 3 and the towed vehicle 2 will move in the same direction without being bent.

After the traveling vehicle 3 and the towed vehicle 2 travel backward in an integral manner, the traveling vehicle 3 travels forward as shown by a switchback FG 3 , and then the traveling vehicle 3 enters the straight-line portion L 1 a . When the traveling vehicle 3 enters the straight-line portion L 1 a , the autonomous traveling controller 61 terminates the multi-point turn control and shifts to a straight-traveling control.

In the straight-traveling control, the autonomous traveling controller 61 sets a steering angle of the steering device 11 so that the traveling vehicle 3 and the towed vehicle 2 are positioned on the straight-line portion L 1 a , that is, so that the traveling vehicle 3 and the towed vehicle 2 travels straight while the relative angle θA is maintained at zero. As shown in FIG. 12 A , when the pivot pin 8 b is positioned on one side (rightward) relative to the straight-line portion L 1 a and the traveling vehicle 3 and towed vehicle 2 are orientated oblique each other in an inverted L-shape, the straight-traveling control sets the steering direction of the traveling vehicle 3 to the one side (rightward) to decrease the relative angle θA so that the traveling vehicle 3 and the towed vehicle 2 are steered to travel on the straight-line portion L 1 a.

As shown in FIG. 12 B , when the pivot pin 8 b is positioned on the other side (leftward) relative to the straight-line portion L 1 a and the traveling vehicle 3 and towed vehicle 2 are orientated oblique each other in an L-shape, the straight-traveling control sets the steering direction of the traveling vehicle 3 to the other side (leftward) to decrease the relative angle θA so that the traveling vehicle 3 and the towed vehicle 2 are steered to travel on the straight-line portion L 1 a . As shown in FIGS. 12 A and 12 B , when the traveling vehicle 3 and the towed vehicle 2 are orientated oblique each other in an inverted L-shape in the straight-traveling control, a steering angle of the steering device 11 may be set based on a magnitude of the relative angle θA or based on a deviation between the straight-line portion L 1 a and the vehicle position.

Thus, since a steering angle and steering direction are controlled based on the relative angle θA, a traveling straightness of the vehicle on the straight-line portion L 1 a can be improved.

FIG. 13 is a view showing autonomous traveling in the autonomous traveling controller 61 . As shown in FIG. 13 , in performing autonomous traveling, the autonomous traveling controller 61 judges whether a vehicle position of the traveling vehicle 3 has reached the turn portion L 1 b from the straight-line portion L 1 a (S 100 ). When the vehicle position of the traveling vehicle 3 has reached the turn portion L 1 b (S 100 , Yes), the autonomous traveling controller 61 judges whether the relative angle θA is less than the turn judgment value θT (S 101 ). When the relative angle θA is less than the turn judgment value θT (S 101 , Yes), the autonomous traveling controller 61 executes the turn control (S 102 ). It is judged whether or not the vehicle position of the traveling vehicle 3 has reached the straight-line portion Lia from the turn portion Lib (S 103 ). When the vehicle position of the traveling vehicle 3 has not reached the straight-line portion Lia from the turn portion Lib (S 103 , No), the autonomous traveling controller 61 returns to S 101 . On the other hand, when the vehicle position of the traveling vehicle 3 has reached the straight-line portion L 1 a from the turn portion L 1 b (S 103 , Yes), the autonomous traveling controller 61 shifts to straight-traveling control (S 104 ). When the relative angle θA is the turn judgment value θT or more (S 101 , No), the autonomous traveling controller 61 stops the turn control and shifts to the multi-point turn control (S 105 ), and when the multi-point turn control ends, the autonomous traveling controller 61 shifts to the straight-traveling control (S 104 ). The autonomous traveling controller 61 controls the steering angle and steering direction so that the traveling vehicle 3 and the towed vehicle 2 positionally match the straight-line portion L 1 a and the relative angle θA is zero in the straight-traveling control.

According to the working vehicle and the working machine described above, since the autonomous traveling is controlled based on the relative angle θA between the traveling vehicle 3 and the towed vehicle 2 , the autonomous traveling can be easily performed even when the traveling vehicle 3 and the towed vehicle 2 connected to the traveling vehicle 3 are autonomously traveling on the scheduled traveling route L 1 . For example, contact between the traveling vehicle 3 and the towed vehicle 2 (that is, vehicle contact) or jackknife phenomenon can be prevented by knowing the relative angle θA during autonomous traveling and controlling at least one of the steering angle and steering direction according to the relative angle θA.

When the traveling vehicle 3 is traveling on the straight-line portion Lia, the traveling vehicle 3 and the towed vehicle 2 can travel so that the positions of both the traveling vehicle 3 and the towed vehicle 2 match the straight-line portion Lia, thus improving the traveling straightness.

In addition, when the traveling vehicle 3 turns left or right on the turn portion Lib, the vehicle contact and the jackknife phenomena can be prevented. In addition, when the relative angle θA between the traveling vehicle 3 and the towed vehicle 2 is large and the turning is difficult, the control can automatically shift from the turn control to the multi-point turn control, and thus the traveling vehicle 3 can return smoothly to the straight-line portion Lia through the turning in multi-point.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.